1. Field of the Invention
This invention relates generally to litter boxes for pets, and more particularly to a litter box having a sifter insert with a foraminous bottom wall which is used to manually remove solids and clumped matter from the litter material without removing or transferring the litter material.
2. Brief Description of the Prior Art
Litter boxes which provide a relief station for cats and other small animals are well known in the art. The conventional litter box consists of a square or rectangular box having an open top end which is typically filled to a depth of one inch or more with granular material simulating fine gravel commonly referred to as "kitty litter". The kitty litter material is discarded and replaced as it becomes soiled. A "clumpable" kitty litter material has become widely accepted because it facilitates cleaning and reusing the litter material. When the "clumpable" litter material becomes soiled with urine or feces, the moisture is absorbed and forms clumps of soiled material which can be removed by lifting them out. However, when the urine or feces is near the bottom or side walls of the box, the clumpable type of material has a tendency to adhere the clumps to the bottom and side wall surfaces.
Others have proposed screen or tray sifting devices through which the litter material is passed or which fit into the litter box and are used to separate solid waste and clumps of soiled material from the litter material.
Vander Wall, U.S. Pat. No. 3,332,397 discloses an ordorless cat toilet comprising an open ended box receptacle having an upper and lower compartment separated by a grill-like wire partition. The litter is disposed in the upper compartment and a deodorizing substance is disposed in the lower compartment. The upper compartment receives the solid fecal matter and liquids and retains the solids and absorbs the bulk of the liquids allowing the excess liquids to drain into the lower compartment. A U-shaped wire guide rod is supported on the grill-like center partition and a wire frame sieve is passed through the litter in the upper compartment to remove the solids. The bottom of the sieve is supported on the U-shaped guide rod to assist in passing the sieve over the grill-like center partition.
Pallesi, U.S. Pat. No. 3,752,120 discloses a cat litter box consisting of three nesting containers, the uppermost having a screen bottom. The uppermost container is filled with sand after being nested over the other two containers. The solid matter is screened by lifting the uppermost container and permitting the sand to fall through the screen into the next lower container. After the refuse laying on the screen has been disposed of, the screen bottom container is nested onto the remaining empty container and the sand is poured into it from the storage container, which when empty is nested under the other containers to become the bottom container.
Larter, U.S. Pat. No. 4,325,325 discloses an arrangement utilizing two containers and a sifter or separator element wherein the first container, the separator, and the second container are stacked one on the other and the assembly is inverted to transfer the litter material from one container into the other while trapping the solids with the separator.
Burniski et al, U.S. Pat. No. 4,616,598 discloses a pet litter box wherein pet litter with accumulated dry solid waste material is held in a tray with a perforated bottom. A flat sheet with identical perforations is slidably engaged with the bottom of the preforated tray. By moving the perforated flat sheet to selectively block off all throughflow (closed mode) to complete congruence of the apertures permitting maximum throughflow (open mode), the user segregates waste matter from reusable litter within the litter box. Waste matter is then discarded and the tray put back into the closed mode and the litter box is turned over to resume operation.
Wilson, U.S. Pat. No. 4,802,442 discloses a cat litter screening device which includes two planar bottom panels of a mesh material that are pivoted together along a central axis and have mesh side panels and handles on each side. To clean the litter material the handle are pulled upwardly which causes the panels to move upwardly through the litter material while folding together to trap fecal matter which is then carried by the device for disposal.
Prince, U.S. Pat. No. 4,817,560 discloses a litter box with a basket-like sifter element that has a foraminous grid formed of intersecting bars of triangular cross section with the apex of the triangle pointing downwardly. The basket-like sifter element is forced downwardly through the litter material and, when it is desirable to remove the solids, the sifter element is lifted upwardly out of the litter box allowing the litter granules to fall back into the litter box while the solids are captured by the basket-like sifter element. This type of sifter construction requires pressing it downwardly and lifting it upwardly through the litter material which does not effectively remove clumps of soiled material that may be adhered to the bottom or side walls of the litter box. Pressing the sifter downwardly also has a tendency to mash the solids which may be beneath the sifter onto the bottom surface of the litter box.
The present invention is distinguished over the prior art in general, and these patents in particular, by a litter box having a sifter insert member that is used to remove solids and clumped matter from the litter material without removing or transferring the litter material. The sifter insert has a foraminous bottom wall, two opposed side walls, one rear end wall, and a transverse front edge extending across the front end of the foraminous bottom wall. The lower portion of the sifter insert is slidably nested in the litter box with its foraminous bottom wall resting on the bottom wall of the litter box. Litter material is sifted by lifting the sifter insert upwardly to capture a substantial portion of solid and clumped material. The sifter insert is reinserted beneath the litter material by holding it in a generally vertical position inwardly adjacent one end wall of the litter box and pushing its front edge downwardly to engage the bottom wall of the litter box and lowering the sifter insert while pushing its front edge along the bottom wall toward the opposed end wall of the litter box until the sifter insert is again nested in the litter box, and thereafter manipulating the litter box to evenly distribute the litter on the sifter insert foraminous bottom wall. The sifter insert may also be used to remove remaining solid and clumped materials by holding it at an angle, inserting its front edge into the litter material and pushing it through the litter material beneath the remaining solid and clumped materials and lifting them out of the litter material.